This application is for a final year of support for the University of Chicago Research Clinic which is participating in the Cooperative Study of Drugs and Coronary Heart Disease. This is a double blind study of 8,395 myocardial infarction survivors, 128 of whom were enlisted locally. These men are receiving one of three drugs or a placebo in accordance with the protocol established by the Steering Committee. It will attempt to establish the effect of the assigned hypocholesteremic drugs upon the course of coronary heart disease and particularly upon the five year survival rate. Already it has been shown that no benefit accrued from the use of dextrothyroxin or two different doses of premarin. Since November of 1972 we have transferred 18 of these patients previously on estrogen or DT4 into the CDP-Aspirin study. We expect to enroll another 4 or 5 eligible patients from the 10 low dose estrogen patients recently transferred to placebo. It is anticipated that all CDP patient visits will be completed by February 28, 1975 at which time clinic activity will cease.